The present invention relates to a detachable boom for fork trucks that is releasably attachable in different ways to a fork truck, but further that is safely retained thereto without dependence on a safety chain.
Some existing boom accessories for fork trucks include a frame adapted to engage the forks of a fork truck, and a boom extending from the frame. When lifted, the forks lift the frame and in turn lift the boom and any object hanging on an end of the boom. Sometimes during use due to an incline of the forks or of the fork truck itself, the forks will be angled slightly downward, such that the boom accessory (and any object carried thereon) will tend to slide forward off the end of the forks (tines). Some boom accessories use a safety chain hooked between the accessory frame and the fork truck's carriage to prevent the accessory frame from accidentally sliding forward off the tines. However, safety chains have been known to be accidentally shaken off or disengaged (or are not properly installed), resulting in a potential risk where the boom accessory and the carried object accidentally come off. This can result in damage to the object being moved and, in some circumstances, cause a safety hazard. A more positive retention mechanism is desired that is less sensitive to operator error and less sensitive to being shaken loose or accidentally dislodged.
Another concern is flexibility of attachment of a boom accessory to fork trucks. Fork trucks and related accessories (such as boom apparatus) require large capital investment, and this investment is inefficiently used when the accessory only fits one fork truck (or only fits one type of fork truck). Thus, companies often take steps to minimize capital expenditure, such as by purchasing a single fork truck with multiple accessories, or by purchasing a flexible accessory that can be used on multiple different fork trucks and/or a combination of those arrangements. However, fork trucks have different carriage and fork tine support structures, such that accessories (such as boom accessories) do not fit on all different fork trucks.